An organic electroluminescent element is a spontaneous light emitting element which utilizes the principle that when an electric field is applied, a fluorescent substance emits light by means of the recombination energy of holes injected from an anode and electrons injected from a cathode. Since the report by C. W. Tang, et al. of Eastman Kodak Company on a low voltage-driven organic electroluminescent element based on a laminated type element (see Non-Patent Document 1), research has been actively conducted on organic electroluminescent elements using organic materials as the constituent materials. Tang, et al. used tris(8-quinolinolato)aluminum in the light emitting layer, and a triphenyldiamine derivative in the hole transport layer. A laminated structure is advantageous in that the efficiency of hole injection into the light emitting layer may be increased, the efficiency for the generation of excitons that are generated by recombination may be increased by blocking electrons injected from the cathode, and the excitons generated in the light emitting layer may be trapped. As the element structure of organic electroluminescent elements such as in this example, a two-layered structure which includes a hole transport (injection) layer and an electron transport and light emitting layer, a three-layered structure which includes a hole transport (injection) layer, a light emitting layer and an electron transport (injection) layer, and the like are well known. In such elements having a laminated type structure, the element structure and the method for forming such a structure have been devised so as to increase the recombination efficiency of injected holes and electrons.
Generally, when an organic electroluminescent element is driven or stored in a high temperature environment, adverse effects occur, such as change in the emitted light color, a decrease in the luminous efficiency, an increase in the driving voltage, and shortening of the emission lifetime. In order to prevent these, it has been necessary to increase the glass transition temperature (Tg) of the hole transporting material. Accordingly, a hole transporting material needs to have many aromatic groups in the molecule (see, for example, Patent Documents 1 and 2: aromatic diamine derivatives of Patent Document 1, and aromatic fused-ring diamine derivatives of Patent Document 2), and conventionally, structures each having 8 to 12 benzene rings have been used with preference.
However, if a substance has a large number of aromatic groups in the molecule, crystallization is prone to occur when a thin film is formed using such a hole transporting material, and an organic electroluminescent element is produced using the thin film. Also, there are problems that the outlet of the crucible used in vapor deposition is blocked, defects attributable to crystallization occur in the thin film, or a decrease in the yield of the organic electroluminescent element may occur. Furthermore, a compound having a large number of aromatic groups in the molecule generally has a high glass transition temperature (Tg); however, such a compound has problems that the sublimation temperature is high, and the service life is short because decomposition at the time of deposition, or an occurrence in which deposition is non-uniformly formed is believed to occur.
Meanwhile, monoamine derivatives having fluorene with aryl groups have been disclosed (see Patent Documents 3 to 8). Patent Document 3 is a patent document related to a photoreceptor. Patent Documents 4 to 8 are patent documents related to organic EL. Particularly, patent document 8 describes an example of using a fluorene-containing monoamine compound in the hole injection/transport layer of an organic electroluminescent element, but a further enhancement of performance is desired.
As discussed above, there have been reports on high-efficiency, long-life organic electroluminescent elements, but there has been a strong demand for an organic electroluminescent element having superior performance.    Patent Document 1: U.S. Pat. No. 4,720,432    Patent Document 2: U.S. Pat. No. 5,061,569    Patent Document 3: Japanese Patent Application Laid-Open No. 7-72639    Patent Document 4: Japanese Patent Application Laid-Open No. 2002-154993    Patent Document 5: Japanese Patent Application Laid-Open No. 2004-043349    Patent Document 6: Japanese Patent Application Laid-Open No. 2003-261471    Patent Document 7: Japanese Patent Application Laid-Open No. 2004-91350    Patent Document 8: Japanese Patent Application Laid-Open No. 11-144875    Non-Patent Document 1: C. W. Tang, S. A. Vanslyke, Applied Physics Letters, Vol. 51, p. 913 (1987)